Show HN: Buildcage – Restrict outbound network access during Docker builds

1 pointsposted 9 hours ago
by dash14

2 Comments

vict00r99

9 hours ago

Hey!Really interesting approach

I’m going to try it in one of my CI pipelines

Quick question: how granular is the allowlist matching, is it exact domain only or do you support wildcards and subdomain patterns

dash14

an hour ago

Thanks for the interest and great question!

The allowlist uses nginx's map directive with the `hostnames` parameter, so it supports several matching patterns:

- Exact domains: `registry.npmjs.org` - Prefix wildcards: `.cloudfront.net` (matches any subdomain) - Suffix wildcards: `github.` (matches github.com, github.io, etc.) - Combined wildcards: `.example.com` (shorthand for both example.com and .example.com) - Regex patterns: `~^.\.amazonaws\.com$` for full PCRE support

Full nginx map documentation: https://nginx.org/en/docs/http/ngx_http_map_module.html

I'll add this to the documentation. Thanks!